97 tahoe, grinding noise

[nhbluevip]

I have a 97 two door tahoe, 5.7L, 4x4, 149000 miles. From the day I got it, It has a grinding noise at interstate speed, in between letting off the gas and pressing the gas. It is still there when letting off the gas, but not as loud as when in between on and off gas. Heres the list of things I have had done, and its still there. New brakes all around. Rear axle seals and fluid. New transmission and transfer case. New universals front and rear drive shafts. New plugs, wires, cap and rotor. Fuel and air filter. rebalanced the tires. It has not changed. It sounds as though in is right under my feet and drivers seat area. Any ideas, Im stumped. Also if on the interstate and you put it in Nuetral the grinding goes away.

 

[Bad bow tie]

Drive shaft or wheel bearing is all I'm coming up with.

 

[SunlitComet]

SInce you have eliminated the tranny and t-case is the noise rate consistant with vehicle speed or engine speed increase or decrease as well?

 

[99Yuk]

Auto-trac 4x4 or manual shifter on floor? Maybe a malfunctioning 4x4 actuator? It sounds like mine does when I'm in 4x4 on the highway. I can make the same sound. Mine is a 99 with a manual shifter on the floor. What if for some reason your 4x4 is not disengaging? I first thought wheel bearing, but it doesn't stop making noise when in neutral rolling along at speed. Then I thought leaky exhaust manifold gasket, but I'm unsure.

 

[nhbluevip]

It is push button 4x4, not on the floor. I thought wheel bearing as well but as already stated, that would be constant, and not go away when put in neatral. It is consistent with vehicle speed, not engine speed.

---------- Post added at 09:20 PM ---------- Previous post was at 09:19 PM ----------

I also forgot to mention, I though it may have been the exhaust hitting somewhere on the body, so I replaced from the muffle back with new stock exhaust. Still the same.

 

[lino5034]

this happened on my tahoe and it was the wheel bearing

 

[96ProCompTahoe]

Is you front shaft spinning with the truck in drive? Front shaft or diff would be my guess if it sounds like it's in the front end and not wheel bearings, drive shafts, trans, brakes, or t-case.

 

[95TwinTT]

Does it make the same sound in 3rd gear as it does in 4th gear?

 

[SunlitComet]

It is push button 4x4, not on the floor. I thought wheel bearing as well but as already stated, that would be constant, and not go away when put in neatral. It is consistent with vehicle speed, not engine speed.

---------- Post added at 09:20 PM ---------- Previous post was at 09:19 PM ----------

I also forgot to mention, I though it may have been the exhaust hitting somewhere on the body, so I replaced from the muffle back with new stock exhaust. Still the same.

What has happened when you shift your transfer case?

 

[nhbluevip]

I dont know if the front drive shaft is spinning while in drive or not. I don't think it is wheel bearings, due to the fact it goes away if put in neutral. I don't believe it is trans or t-case, because it has a completely different trans and t-case then before, and nothing has changed, as far as the grinding noise. Im at a lose. Also not the breaks because i have put all new pads rotors and rear drums on the truck, and still no change. Also if it were the tires, it again would still make the noise wether it was in drive or neutral.

---------- Post added at 01:42 AM ---------- Previous post was at 01:41 AM ----------

I also forgot to mention it goes into 4x4 fine, no noises.